1. Field of the Invention
The present invention relates to novel Lewis acid fluorine compounds of carbon and their method of preparation.
2. Prior Art
As is well known, carbon exists in a number of different allotropic forms. Of particular interest from a chemical point of view is the highly crystalline form of carbon known as graphite and the amorphous forms of carbon, such as charcoal and lampblack. Because of the differences in allotropy, the amorphous and crystalline forms of carbon do not have completely analogous chemical reactivity. Thus, for example, graphite forms intercalation compounds with a wide variety of materials. These inclusion or intercalation compounds have been described as being heteropolar because of their ionic character. See, for example, Angew. Chem. Internat Edit., Vol. 2, No. 2, p. 67-73 (1963). Indeed, graphite has been shown to form blue graphite salts with sulfates and nitrates. In particular, the nitrate salt of graphite, [3HNO.sub.3 -]C.sub.24.sup.+, has been shown to have a conductivity which approaches that of copper. See, Proc. Roy. Soc. Lond., A325, p. 437 (1971). Graphite also has been reported to form intercalation compounds with hydrogen fluoride, see, for example, Russian J. of Inorg. Chem., 17, p. 632 (1972), and with hydrogen fluoride and chlorine trifluoride, see, for example, Russian J. Inorg. Chem., 17, p. 1366 (1972).
In U.S. Pat. No. 3,844,837, lamellar graphite compounds, such as the tetrafluoroborate salt of graphite, are described. These compounds were prepared by impressing an electric current between an anode and a graphite cathode immersed in a nonagueous salt solution such as a nonaqueous solution of lithium tetrafluoroborate. In any event, the electrochemical intercalation suggested by the patent disclosure does not lead to fully intercalated materials of graphite, commonly referred to as "first stage compounds."